Access device

ABSTRACT

An access device places a medical article within a body space of a patient. The device has a needle that includes an elongated body and a needle hub. The device further includes a dilator disposed on and slideable along the elongated body of the needle and a medical article. The medical article is disposed on and slideable along the dilator. A track extends in a proximal direction from the dilator. The needle hub slides along at least a portion of the track between a first position and a second position. The device further includes a locking mechanism operably disposed between the track and the needle hub so as to inhibit further axial movement of the needle in the proximal direction when the needle hub is in the second position.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 12/106,196, filed Apr. 18, 2008, which is related to and claimsthe benefit under 35 U.S.C. §119(e) to U.S. Provisional PatentApplication Ser. Nos. 60/912,645 (filed Apr. 18, 2007), 60/948,136(filed Jul. 5, 2007), and 61/036,900 (filed Mar. 14, 2008), all of whichare hereby expressly incorporated by reference in their entireties.

BACKGROUND

1. Field of the Invention

This invention is generally directed to access devices for introducingand/or delivering a medical article (such as, for example, a catheter,cannula, sheath, etc.) into a body space, such as, for example, anartery, vein, vessel, body cavity, or drainage site.

2. Description of the Related Art

A preferred non-surgical method for inserting a catheter or vascularsheath into a blood vessel involves the use of the Seldinger or amodified Seldinger technique, which includes an access needle that isinserted into a patient's blood vessel. A guidewire is inserted throughthe needle and into the vessel. The needle is removed, and a dilator andsheath in combination or separately are then inserted over theguidewire. The dilator and sheath, together or separately, are theninserted a short distance through the tissue into the vessel, afterwhich the dilator and guidewire are removed and discarded. A catheter orother medical article may then be inserted through the sheath into thevessel to a desired location, or the sheath may simply be left in thevessel.

A number of vascular access devices are known. U.S. Pat. Nos. 4,241,019,4,289,450, 4,756,230, 4,978,334, 5,124,544, 5,424,410, 5,312,355,5,212,052, 5,558,132, 5,885,217, 6,120,460, 6,179,823, 6,210,332,6,726,659 and 7,025,746 disclose examples of such devices. None of thesedevices, however, has the ease and safety of use that physicians andother healthcare providers would prefer. Thus, there exists a need foran easier-to-use and safer vascular access device, especially one thatwould clearly and promptly indicate when a blood vessel has beenpunctured and one that would reduce accidental needle sticks and otherattendant risks of over-wire vascular access.

SUMMARY

Embodiments of the present invention involve several features for anaccess device useful for the delivery of a catheter or sheath into aspace within a patient's body, such as, for example, a blood vessel ordrainage site. Without limiting the scope of this invention, its moreprominent features will be discussed briefly. After considering thisdiscussion, and particularly after reading the Detailed Description ofthe Preferred Embodiments section below in combination with thissection, one will understand how the features and aspects of theseembodiments provide several advantages over prior access devices.

One aspect of the present invention is an access device for placing amedical article within a body space. The device includes a needle thathas an elongated needle body with a distal end and a hub from which theneedle body extends. The device further includes a dilator disposed onthe needle body. The needle and the dilator are moveable relative toeach other from a first position, wherein the distal end of the needlelies distal of the dilator, and a second position, wherein the distalend of the needle lies within the dilator. The dilator includes adilator hub and an elongated dilator shaft that extends from the dilatorhub. The device further includes a locking mechanism that operatesbetween the needle and the dilator to inhibit movement of the needlerelative to the dilator when in the second position. The lockingmechanism is configured to allow movement of the needle from the firstposition toward the second position without engagement by the lockingmechanism so as to lessen resistance to the movement.

Another aspect of the invention is an access device for placing amedical article within a body space. The device includes a needle thathas a needle body with a longitudinal axis, a distal tip, and a needlehub from which the needle body extends. The device further includes adilator that has a dilator shaft and a dilator hub. The dilator shaft isdisposed on and slideable along the needle body with the dilator hubbeing disposed distal of the needle hub. The device further includes amedical article that has a tubular section and a hub. The tubularsection is disposed on and slideable along the dilator with the hubbeing disposed distal of the dilator hub. The device includes a trackthat extends from the dilator hub in a proximal direction and a lockingmechanism operably disposed between the track and the needle hub so asto selectively inhibit proximal movement of the needle relative to thedilator.

Yet another aspect of the invention is an access device for placing amedical article within a body space. The device includes a needle thathas a distal end and a first fenestration. The device further includes adilator disposed on and slideable along the needle and has a secondfenestration. One of the first and second fenestrations has a greaterdimension in at least one direction than the other one of the first andsecond fenestrations in said direction. The device further includes amedical article being coaxially disposed and longitudinally movable overthe dilator.

Yet another aspect is an access device for placing a medical articlewithin a body space. The device includes a needle having a distal endand at least one fenestration. The device further includes a dilatorthat has a shaft disposed on at least a portion of the needle. Thedevice further includes a medical article disposed on at least a portionof the dilator and at least one elongated channel disposed between theneedle and an exterior surface of the medical article that extends alongat least a substantial portion of the length of the dilator shaft. Thechannel communicates with the fenestration in the needle and has a spanangle of less than 360 degrees about a longitudinal axis of the dilator.

Another aspect involves a pre-assembled access device for placing amedical article within a body space. The device includes a needle havinga distal end with at least one fenestration and a dilator including ashaft coaxially disposed about at least a portion of the needle. Thedevice further includes a medical article coaxially disposed about atleast a portion of the dilator and at least one elongated channel formedbetween the needle and the exterior surface of the medical article. Thechannel extends along at least a substantial portion of the length ofthe dilator shaft. The channel communicates with the fenestration in theneedle. The channel is defined at least in part by a groove formed on aninner surface of the medical device, on an outer surface of the dilator,on an inner surface of the dilator, or a combination of such grooves. Insome modes, the groove extends only partially around a longitudinal axisof the needle, and in other modes the groove spirals along the axis.

Still another aspect is a method of removing a needle and dilatorassembly from a patient where the dilator is coaxially disposed about atleast a portion of the needle. The method includes moving a needlerelative to a dilator from a first position to a second position. Adistal end of the needle lies distal of the dilator in the firstposition. The distal end of the needle lies within the dilator in thesecond position. The method further comprises inhibiting furthermovement of the needle relative to the dilator once the needle is in thesecond position.

A further aspect involves an access device for placing a medical articlewithin a body space. The access device comprises a needle having adistal end and a longitudinal axis, and a dilator disposed on at least aportion of the needle and having an outer surface. A medical article isdisposed on at least a portion of the dilator and has an inner surface.At least a portion of the inner surface of the medical article or aportion of the outer surface of the dilator has a dissimilar shape tothat of an adjacent portion of the outer surface of the dilator or innersurface of the medical article (respectively) so as to form a gaptherebetween, which extends along the longitudinal axis.

A releasable interlock can be provided in some embodiments to inhibitrelative rotational movement between the needle and the dilator, atleast when the needle is inserted into a patient. By inhibiting suchrelative rotational movement, communicating fenestrations in the needleand the dilator can be held in alignment to provide a simplified channelthrough which the blood or fluid may flow. Thus, when the needle entersa blood vessel or drainage site in the patient, blood or other bodyfluid quickly flows into the channel. The resulting blood or fluid flashis visible through the sheath (or catheter) to indicate that the needletip has entered the vessel or drainage site.

For example, but without limitation, the dilator can comprise, in someembodiments, a dilator hub and dilator having one or more sidefenestrations. The dilator hub may have a luer connection and areleasable locking mechanism. The releasable locking mechanism can beconfigured to releasably engage and secure the dilator to another part,such as the needle hub. When the needle hub and the dilator hub arereleasably locked to prevent rotation therebetween, at least a portionof one or more of the side fenestrations in the dilator are aligned withat least a portion of one or more side fenestrations in the needle. Thelocking mechanism can also be configured to inhibit unintentionalrelative axial movement between the needle and the dilator.

The medical article preferably, but not necessarily, includes a sheathand sheath hub. The sheath may be made partially or completely from aclear, translucent, semi-opaque, or transparent material. Suchtransparent, translucent, semi-opaque and clear materials allow aclinician the ability to see when blood or other body fluids flows intothe needle, through the needle fenestration(s), through the side dilatorfenestration(s), and into the viewing space between the dilator andsheath. The sheath may also have radiopaque stripes so disposed as notto obscure the viewing space.

These and other aspects of the present invention will become readilyapparent to those skilled in the art from the following detaileddescription of the preferred embodiments, which refers to the attachedfigures. The invention is not limited, however, to the particularembodiments that are disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the access devicedisclosed herein are described below with reference to the drawings ofpreferred embodiments, which are intended to illustrate and not to limitthe invention. Additionally, from figure to figure, the same referencenumerals have been used to designate the same components of anillustrated embodiment. Like components between the illustratedembodiments are similarly noted as the same reference numbers with aletter suffix to indicate another embodiment. The following is a briefdescription of each of the drawings.

FIG. 1A is a perspective view of a preferred embodiment of an accessdevice configured in accordance with the present invention and shows apre-loaded guidewire section coaxially aligned with a needle, a dilator,and a medical article.

FIG. 1B is a plan view of the embodiment depicted in FIG. 1A.

FIG. 2A is a plan view of the needle from FIG. 1A and shows afenestration near a distal end.

FIG. 2B is a side view of the needle from FIG. 1A and shows a fin near aproximal end.

FIG. 2C is a cross-sectional view taken along the lines 2C-2C in FIG.2A.

FIG. 2D is an enlarged plan view of a portion of the needle of FIG. 2Aand shows the fenestration.

FIG. 2E is an enlarged plan view of the needle hub of the needle of FIG.2A.

FIG. 2F is an enlarged side view of the needle hub of the needle of FIG.2A.

FIG. 2G is an enlarged proximal end view of the needle hub of the needleof FIG. 2A.

FIG. 3A is a plan view of the dilator from FIG. 1A and shows afenestration near a distal end. FIG. 3A also shows longitudinallyarranged grooves in the luer surface for venting air from between thedilator and sheath.

FIG. 3B is a cross-sectional view taken along the lines 3B-3B in FIG.3A.

FIG. 3C is an enlarged plan view of a portion of the dilator from FIG.3A and shows the fenestration and longitudinal channel.

FIG. 3D is an enlarged end view of the dilator hub from FIG. 3A.

FIG. 3E is a perspective view of another embodiment of the dilator hubthat includes a locking spin nut configured to secure to a sheath thathas a corresponding screw thread.

FIG. 3F is a cross-sectional view taken along the lines 3F-3F in FIG. 3Aand shows the grooves equally spaced about the circumference of the luersurface.

FIG. 4A is a plan view of the sheath from FIG. 1A and shows a sheath hubconnected to a proximal end of a sheath.

FIG. 4B is a cross-sectional view taken along the lines 4B-4B in FIG.4A.

FIG. 4C is an enlarged end view of the sheath from FIG. 4A.

FIG. 4D is an enlarged perspective view of a proximal portion of thesheath from FIG. 4A.

FIG. 5A is a perspective view of the guidewire section from FIG. 1A andshows a guidewire hub connected to a proximal end of a guidewire.

FIG. 5B is a plan view of the guidewire section of the embodimentdepicted in FIG. 5A.

FIG. 6A is a perspective view of a track from FIG. 1A.

FIG. 6B is a plan view of the track in FIG. 6A and shows a lockingmechanism for locking the needle relative to the dilator.

FIG. 6C is a side view of the track in FIG. 6B.

FIG. 6D an enlarged view of the locking mechanism from FIG. 6B.

FIG. 6E is an enlarged view of another locking mechanism that locks theguidewire section in a pre-loaded state.

FIG. 7A is a plan view of the access device from FIG. 1A and shows thelocking mechanism from FIG. 6E with the guidewire section locked to thetrack in the pre-loaded state.

FIG. 7B is a side view of the access device and locking mechanism fromFIG. 7A.

FIG. 7C is a cross-sectional view through the access device of FIG. 7Aand shows the guidewire hub disposed between an element and stop of thetrack.

FIG. 7D is an enlarged end view of the access device from FIG. 7B andshows two arms extending from the track and around at least a portion ofthe guidewire hub.

FIG. 8A is a plan view of the embodiment depicted in FIG. 1Aillustrating the insertion of the distal end of the access device into apatient.

FIG. 8B is an enlarged view of the embodiment depicted in FIG. 8Afocusing on the area of the access device adjacent to the patient.

FIG. 8C is an enlarged view of a portion of the embodiment depicted inFIG. 8B and illustrates the needle opening or fenestration aligned withthe dilator opening or fenestration in hidden lines.

FIG. 8D is an enlarged cross-sectional view of a portion of theembodiment depicted in FIG. 8C and shows the needle opening orfenestration aligned with the dilator opening or fenestration so as toallow fluid to flow from inside the needle to a channel formed betweenthe sheath and dilator.

FIG. 8E is a graph showing the rate fluid is drawn up a channel with agap height width of 0.002 inches.

FIG. 8F is a graph showing the rate fluid is drawn up a channel with agap height width of 0.001 inches.

FIG. 8G is a graph showing the rate fluid is drawn up a channel with agap height width of 0.0005 inches.

FIG. 8H is an enlarged cross-sectional view of a portion of theembodiment depicted in FIG. 8C taken through a region distal of thechannel in the dilator.

FIG. 8I is an enlarged view of the embodiment depicted in FIG. 8Afocusing on the area where the needle hub is locked to the dilator hubwhen the needle hub is in the first position.

FIG. 8J is a cross-sectional view of the embodiment depicted in FIG. 8I.

FIG. 9A is a side view of the embodiment depicted in FIG. 1Aillustrating the guidewire advanced from the needle tip in a distaldirection.

FIG. 9B is an enlarged view of the embodiment depicted in FIG. 9Afocusing on the area where the guidewire hub is locked to the needle hubwhen the needle hub is in the first position.

FIG. 9C is a cross-sectional view of the embodiment depicted in FIG. 9B.

FIG. 10A is a side view of the embodiment depicted in FIG. 1Aillustrating the dilator and sheath being advanced distally relative tothe needle body from the position illustrated in FIG. 9A.

FIG. 10B is an enlarged rear view of the embodiment depicted in FIG. 10Afocusing on the area where the needle hub is locked to the track whenthe needle hub is in the second position.

FIG. 11A is a side view of the embodiment depicted in FIG. 1Aillustrating the removal of the guidewire, needle body, and dilator fromthe sheath.

FIG. 11B is an enlarged view of the portion of the embodimentillustrated in FIG. 11A showing the needle tip covered by the dilatorduring removal of the guidewire, needle body, and dilator from thesheath.

FIG. 12A is an enlarged plan view that illustrates another embodiment ofthe aligned openings or fenestrations in the needle and dilator.

FIG. 12B is an enlarged cross-sectional view along lines 13B-13B in FIG.12A and shows the needle opening or fenestration aligned with thedilator opening or fenestration so as to allow fluid to flow from insidethe needle to a channel formed between the sheath and dilator.

FIG. 13A is an enlarged plan view that illustrates another embodiment ofthe aligned openings or fenestrations in the needle and dilator.

FIG. 13B is an enlarged cross-sectional view along lines 13B-13B in FIG.13A and shows the needle opening or fenestration aligned with thedilator opening or fenestration so as to allow fluid to flow from insidethe needle to a channel formed between the sheath and dilator

FIG. 14A is an enlarged plan view that illustrates another embodiment ofthe channel formed between the dilator and the sheath.

FIG. 14B is a cross-sectional view along lines 14B-14B in FIG. 14A andshows the thickness of the channel extending into the sheath.

FIG. 15A is an enlarged plan view that illustrates another embodiment ofthe channel formed between the dilator and the sheath.

FIG. 15B is a cross-sectional view along lines 15B-15B in FIG. 15A andshows the thickness of the channel extending into both the dilator andthe sheath.

FIG. 16A is an enlarged plan view that illustrates another embodiment ofthe channel formed between the dilator and the sheath.

FIG. 16B is a cross-sectional view along lines 16B-16B in FIG. 15A andshows a plurality of equally spaced channels in the form of splinesextending into the dilator.

FIG. 17 is an enlarged cross-sectional view through another embodimentof the access device and shows the channel formed between a sheath and adilator that have dissimilar shapes.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present disclosure provides an access device for the delivery of amedical article (e.g., catheter or sheath) to a blood vessel or drainagesite. FIG. 1A illustrates an access device 20 that is configured to beinserted into a blood vessel (e.g., a vein or an artery) in accordancewith a preferred embodiment of the present invention. While the accessdevice is described below in this context (i.e., for vascular access),the access device also can be used to access and place a medical article(e.g., catheter or sheath) into other locations within a patient's body(e.g., a drainage site) and for other purposes (e.g., for draining anabscess).

The present embodiment of the access device is disclosed in the contextof placing an exemplary single-piece, tubular medical article into abody space within a patient. Once placed, the tubular article can thenbe used to receive other medical articles (e.g., catheters, guidewires,etc.) to provide access into the body space and/or be used to provide apassage way for introducing fluids into the body space or removing(e.g., draining) fluids from the body space. In the illustratedembodiment, the tubular medical article is a sheath or catheter that isconfigured primarily to provide a fluid passage into a vein. Theprinciples of the present invention, however, are not limited to theplacement of single piece sheaths or catheters, or to the subsequentinsertion of a medical article via the sheath or catheter. Instead, itwill be understood by one of skill in this art, in light of the presentdisclosure, that the access device disclosed herein also can besuccessfully utilized in connection with placing one or more other typesof medical articles, including other types of sheaths, fluid drainageand delivery tubes, and single or multi-lumen catheters directly in thepatient or indirectly via another medical article.

For example, but without limitation, the access device disclosed hereincan also be configured to directly or indirectly place central venouscatheters, peripherally inserted central catheters, hemodialysiscatheters, surgical drainage tubes, tear-away sheaths, multi-piecesheaths, scopes, as well as electrical conduit for wires or cablesconnected to external or implanted electronic devices or sensors. Asexplained above, the medical articles listed above may be directlyplaced in the patient via the dilator, needle, and guidewire of theaccess device or subsequently placed within the patient via a medicalarticle that was placed within the patient via the dilator, needle, andguidewire of the access device.

Further, the embodiments disclosed herein are not limited to co-axialinsertion of a single medical article. For example, two catheters may beinserted in the patient via an inserted sheath or a second catheter maybe inserted in the patient via an inserted first catheter. Further, inaddition to providing a conduit into the vessel or other body space, themedical article inserted via the dilator, needle, and guidewire can forma lumen that is in addition to the lumen(s) of the subsequently insertedmedical article. One skilled in the art can also find additionalapplications for the devices and systems disclosed herein. Thus, theillustration and description of the access device in connection with asheath (e.g., for micro puncture applications) is merely exemplary ofone possible application of the access device.

FIGS. 1A and 1B illustrated a preferred embodiment of an access device20. The access device 20 comprises a needle 22, a dilator 24, and asheath 26. In the illustrated embodiment, the access device alsoincludes a guidewire section 28 and a track 30. As best seen in FIG. 1B,the dilator 24 is preferably coaxially mounted on the needle 22, and thesheath 26 is coaxially mounted on the dilator 24. The telescoping natureof the access device's components can also be accomplished by arrangingthe components with their axes arranged substantially parallel ratherthan coaxially (e.g., a monorail-type design).

Each of these components includes a luminal fitting at a terminal end ortransition (i.e., a hub) and elongated structure that extends from thefitting. Thus, in the illustrated embodiment, the needle 22 includes aneedle body 32 that extends distally from the needle hub 34, the dilator24 includes a dilator shaft 36 that extends distally from a dilator hub38, and the sheath 26 includes a sheath body 40 that extends distallyfrom a sheath hub 42. The guidewire section 28 comprises a guidewire 44and preferably a guidewire hub or cap 46. In the illustrated embodiment,the guidewire hub 46 is disposed on the proximal end of the guidewire44; however, in other applications, the hub 46 can be disposed at alocation between the ends of the guidewire 44.

FIGS. 2A-2G illustrate the needle body 32 and needle hub 34 of theneedle 22, which are configured in accordance with a preferredembodiment of the access device, in isolation from the other componentsof the access device 20. As best seen in FIGS. 2A and 2B, the needle hub34 is disposed on a proximal end of the needle body 32. The needle body32 terminates at a distal end near a distal portion 50 of the needle 22,and the needle hub 34 lies at a proximal portion 52 of the needle 22.

The needle body 32 preferably has an elongated tubular shape having acircular, constant-diameter inner bore and a circular, constant-diameterexterior surface. In other embodiments, however, the needle body 32 canhave other bore and exterior shapes (such as, for example, but withoutlimitation, an oval cross-sectional shape). The interior or exterior ofthe needle can also include grooves or channels. The grooves or channelsmay guide fluids within the needle bore either around or to certainstructures of the needle 22 or within the needle 22 (e.g., around theguidewire). In some embodiments, the grooves or channels may assist inmaintaining a desired orientation of the needle 22 with respect to thedilator.

The needle body 32 has a sufficiently long length to access a targetedsubcutaneous body space and has a sufficient gauge size to withstand theinsertion forces when accessing the body space without causing unduetrauma. For many applications, the needle body can have a length between3-20 cm, and more preferably between 3-10 cm. For example, to access abody space (e.g., a vessel) in the thorax of an adult human, the needlebody 32 preferably has a length of 7 cm or greater, and more preferablyhas a length of 9 cm or greater, and most preferably has a length of 9to 10 cm. The size of the needle preferably is 18 gauge or smaller, andmore preferably between 18-28 gauge, and most preferably between 18-26gauge for micro-puncture applications (peripheral IVs). For applicationswith a neonate, the length and gauge of the needle body 32 should besignificantly shorter and smaller, for example preferably between 3-4 cmand between 26-28 gauge.

As best seen in FIGS. 2A and 2D, the needle body 32 includes at leastone fenestration or opening 56 near a distal end of the needle body 32.The fenestration 56 extends through the wall of the needle body 32 andcan have a variety of shapes and orientations on the needle body 32, asdescribed in detail below. In addition, the needle body 32 can have abevel tip 54 disposed on the distal portion 50.

As is illustrated in FIG. 2A, the fin 58 is preferably disposed at acircumferential location around the needle hub 34 that is aligned withthe circumferential locations of the bevel on the needle tip and theopening or fenestration 56 in the needle. That is, the fin 58 is indexedwith the bevel and fenestration. During use, the physician or healthcareprovider can determine the orientation of the beveled needle tip (andthe fenestration 56) by noting the orientation of the exposed fin 58even though the bevel is inside the vessel and the fenestration iscovered by the sheath and/or dilator. For example, in the illustratedembodiment, an orientation of the fin 58 away from the patient coincideswith a bevel up orientation of the needle tip within the vessel. Thefenestration 56 is also on the same side as the fine 58, as seen in FIG.2C.

As shown most clearly in FIG. 2B, the illustrated embodiment of theneedle hub 34 has a finger-hold, tab or fin 58. The fin 58 provides agrasping region to manipulate the needle hub 34. For example, aphysician or healthcare provider can place an index finger and thumb onthe sides of the fin 58 to stabilize the needle hub 34, relative to thedilator 24 and/or sheath 26. In the illustrated embodiment, as thedilator/sheath slides distally over the needle, the needle hub 34 slidesrelatively along the track 30 between a first position 121 and a secondposition 123. The fin 58 can be held when performing the insertion step(which will be described below). In addition, the fin 58 can be used tostabilize the needle hub 34 while rotating the dilator hub 38.Furthermore, the fin 58 can be used by a physician or healthcareprovider as an aid to grasp the access device 20 when the needle hub 34is disposed at any position along the track 30.

FIG. 2D is an enlarged view of the side opening or fenestration 56 inthe needle body 32. The one or more fenestration 56 provides a paththrough the side of the needle body 32. The fenestration 56 illustratedin FIG. 2D has an oblong shape. The shape of the side opening 56,however, is not limited to the illustrated embodiment and may be round,oblong, square, or another shape.

With specific reference now to FIGS. 2E-2G, the needle hub 34 preferablyincludes locking structures at the proximal portion and distal portionof the needle hub 34. These locking structures may be a luer-thread-typeor another type of connections.

The locking structure on the proximal portion 52 of the needle hub 34allows the physician or healthcare provider to secure another medicalarticle to the proximal end of the needle hub 34. For example, theneedle hub 34 in the illustrated embodiment includes an annular flangeor lip 63. The lip 63 is threaded to allow the needle hub 34 to attachto other medical articles with a corresponding luer-nut locking feature.Additionally, a physician or healthcare provider may attach a syringe ormonitoring equipment to the locking structure on the proximal end toperform other procedures as desired. The needle hub 34 can also includea septum at its proximal end and/or a side port if these features aredesirably for a particular application.

The locking structure on the distal portion of the needle hub 34 allowsthe physician or healthcare provider, for example, to lock the needlehub 34 to the dilator hub 38 when the needle hub 34 is in the firstposition 121. In the illustrated embodiment, the locking structureincludes a latch element 66 on the needle hub 34. The latch element 66releasably locks the needle hub 34 to the dilator hub 38. The lockingstructure allows the healthcare provide to advance the needle into apatient while grasping the needle hub 34, the dilator hub 38 or both.

As explained below in greater detail, the guidewire 44 is introducedthrough a hollow portion 62 of the needle hub 34, through the needlebody 32, and into a punctured vessel. The guidewire 44 allows thehealthcare provider to guide the dilator 24 and sheath 26 into thevessel.

The needle hub 34 may also comprise two tangs 68 that allow the needlehub 34 to slide along the track 30 between a first position 121 and asecond position 123. While in the preferred embodiment the two tangs 68of the needle hub 34 are engaged with the track 30 between the firstposition 121 and the second position 123, in other embodiments theneedle hub 34 is only engaged with the track 30 over a portion of thelength of the track 30 between the first position 121 and the secondposition 123. The sliding interconnection between the track 30 and theneedle hub 34 also can be accomplished using other cooperatingstructures (e.g., a corresponding pin and tail of dovetail connection).

FIG. 3A is a plan view of the dilator 24 of the embodiment depicted inFIG. 1A. FIG. 3B is a cross-sectional view of the dilator 24 of theembodiment depicted in FIG. 3A, taken along line 3B-3B. As shown inFIGS. 3A and 3B, the illustrated dilator 24 comprises a dilator shaft36, a dilator hub 38, a distal region 70, and a proximal region 72. Inthe illustrated embodiment, the dilator shaft 36 includes a sideopenings or fenestrations 74; however, in other embodiments, the dilatorshaft 36 can include fewer or greater numbers of fenestrations 74. Forexample, the dilator shaft 36 may not include a fenestration 74 where ablood flash chamber(s) is disposed within the dilator (as will bedescribed in more detail below).

The dilator hub 38 may comprise one or more vents. In the illustratedembodiments, the vents in the dilator hub 38 are formed by grooves 75.Additionally, the dilator shaft 36 may comprise one or more longitudinalchannels formed in the outer surface of the dilator shaft 36. In theillustrated embodiment, the channel is an open channel. The side wallsof the open channel are formed by ridges 76. In the illustratedembodiment, the ridges 76 define generally smooth, arcuate exteriorsurfaces that interface with the sheath 26; however, in otherembodiments, the ridges can have other shapes (e.g., can defined morepronounced apexes). Once assembled within a sheath body 40, the openchannel in the dilator shaft 36 is closed by the inside diameter of thesheath body 40.

FIG. 3C is an enlarged plan view of a portion of the embodimentillustrated in FIG. 3A. As noted above, the illustrated dilator shaft 36comprises one or more side openings 74 and one or more channels formedbetween ridges 76. The side opening or fenestration 74 provides a fluidpath through the side of the dilator shaft 36. The shape of the sideopening 74 is not limited to the illustrated embodiment and may beround, oblong, square, or have another shape. The opening orfenestration 74 illustrated in FIG. 3C has an oblong shape.

In the illustrated embodiment, the opening 74 in the dilator shaft 36has an oblong shape with its major axis being non-parallel relative tothe major axis of the oblong opening 56 in the needle. For example theneedle opening 56 may extend in a longitudinal direction and the dilatoropening 74 may extend in a circumferential direction or vice versa. Inother words, the long axis of the dilator opening 74 is disposedgenerally perpendicular to the long axis of the needle opening 56. Asexplained in connection with additional embodiments below, theseopenings 56, 76 can have other shapes, sizes and orientations thatpreferably obtain a significant degree of overlap to account formanufacturing tolerances and rotational misalignments. For this reason,it is preferred that one of the fenestrations has a greater dimension inat least one direction than the other one of the fenestrations in thesame direction. Accordingly, in the illustrated embodiment, the needlefenestration 56 has a longer longitudinal dimension than thelongitudinal dimension of the dilator fenestration 74.

The channel formed between the ridges 76 extends in a proximal directionfrom a point distal to the opening 74. The ridges 76 in the illustratedembodiment are disposed along the dilator shaft 36 and on opposite sidesof the dilator shaft 36 so as to balance the dilator shaft 36 within thesheath. In the illustrated embodiment, the ridges 76 form two channelsthere between. Balancing the dilator within the sheath allows thedilator to apply equal pressure to the inside circumference of thesheath.

The dilator hub 38 may include locking structures at the proximal region72 and the distal region of the dilator 24. Each locking structure maybe a luer type or other type of connection. In the illustratedembodiment, the dilator hub 38 comprises a first luer connection 78, asecond luer connection 80, a lip 77, and a base 79. The first luerconnection 78 engages to the needle hub 34 on the needle 22 illustratedin FIG. 2E. The second luer connection 80 is disposed distal to thefirst luer connection 78. In some embodiments, the second luerconnection 80 (e.g., a male luer slip connector) can be configured toengage to the sheath hub 42 (e.g., a female luer slip connector) on thesheath 26 illustrated in FIG. 1A. Additionally, the male-female lureslip connectors on these components can be reversed.

FIG. 3D is an enlarged proximal end view of the dilator 24 of FIG. 3A.As shown most clearly in FIG. 3D, the dilator hub 38 comprises anopening 82 that releasably engages the latch element 66 on the needlehub 34 illustrated in FIG. 2E-2F to secure the dilator hub 38 to theneedle hub 34 when the needle hub 34 is in the first position 121.Again, the male-female lure slip connectors on the dilator hub and theneedle hub 34 can also be reversed in other embodiments.

The color of the dilator 24 may be selected to enhance the contrastbetween the blood or other fluid and the dilator 24. During blood flash,for example, blood is observed flowing between the dilator 24 and thesheath to confirm proper placement of the needle in a blood vessel. Toincrease the visibility of the fluid as the fluid flows between thesheath and dilator 24, the sheath is preferably manufactured from aclear or transparent material with the dilator 24 having a color thatcontrasts with the color of the fluid. For example, the dilator 24 mayhave a white color to enhance its contrast with red blood. Other colorsof dilator 24 could be employed depending on the color of the fluid andthe degree of contrast desired. Further, only a portion of the dilatorin the region of the blood flash can have the contrasting color with theremainder having a different color. For embodiments that have a channelformed between the needle and dilator 24, the dilator 24 may bemanufactured of a clear or transparent material similar to the sheath toallow the physician to observe the blood flash through both the sheathand dilator 24.

FIG. 3E is an enlarged perspective view of another embodiment of adilator hub 38A. The dilator hub 38A is similar to the dilator hub 38illustrated in FIG. 3A except that the dilator hub 38A further includesa spin nut or collar 84. The proximal end of the spin nut 84 rotatesabout an annular groove 73 in the dilator hub 38 (see FIG. 3A). Oncedisposed within the annular groove 73, the spin nut 84 is inhibited frommoving in the distal direction but is free to rotate about the dilatorhub 38A. The spin nut 84 can have an interengaging element that locks toa corresponding interengaging element on the sheath 26. In theillustrated embodiment, the spin nut 84 includes an internal threadwhich engages with an external thread on the sheath hub 42 on the sheath26 illustrated in FIG. 1A.

The dilator 24 or sheath 26 may separately, or together, form one ormore passages to allow air or gas to escape or vent from between thedilator 24 and sheath 26 and/or between the needle and the dilator. Theone or more passages may further be sized to inhibit the flow of aliquid, such as blood, while allow air to pass therethrough. The one ormore passages may be in the wall of the sheath 26, the sheath hub, thedilator hub 38, an exposed section of the dilator shaft, and/or formedbetween adjacent surfaces of the dilator 24 and sheath 26. For example,FIG. 3A shows longitudinally arranged grooves 75 that are formed betweenadjacent surfaces of the dilator 24 and sheath 26. Such venting passagescan also be labyrinth. The adjacent surfaces form a luer slip connectionbetween the sheath 26 and dilator 24.

FIG. 3F is a cross-sectional view taken along lines 3F-3F in FIG. 3A andshows the grooves 75 equally spaced, though not required to be equallyspaced, about the circumference of the luer slip surface. The grooves 75are sized to allow air to escape from between the dilator and themedical article, such as a sheath, when the blood flash occurs. Asmentioned above, the one or more passages need not be in the form of asurface groove 75 and instead may be in the form of an opening orpassageway.

In the illustrated embodiment, the one or more passages allow air topass through the luer connection between the sheath and dilator hubs. Inthe illustrated embodiment, a distal end of the passage 75 or is locatedon the distal side of the luer connection with the proximal end of thepassage 75 being located on the proximal side of the luer connection.

The one or more passages may be sized to filter blood or other liquid ormay include a filter or other structure that inhibits the passage of aliquid while allowing the passage of air. For example, the sheath itselfmay include one or more passages in the form of small openings, pores orporous material. Depending on the size of the one or more passages andthe expected size of the fluid molecules and formed elements (e.g. redblood cells), the one or more small openings, pores or porous materialin the sheath can form a porous vent that allows air to pass yet retainblood.

A method of manufacturing a ridged dilator will now be described. First,an extrusion process is used to create a long tubular body having one ormore longitudinal grooves or channels on its outer diameter (OD) orwithin the substance of the dilator. The long tubular body exceeds therequired length of a single dilator and preferably has a length that ismany times greater than the length of a single dilator. A manufacturingdie is employed in the extrusion process having geometry that reflectsthe desired geometry for the inside and outside diameters of the dilatorand the thickness and circumferential span of the longitudinal groovesor channels or interior channels. In the illustrated embodiment of FIGS.1-11, the long tubular body includes two longitudinal OD channels onopposite sides of the body to enhance the balance of the dilator withinthe sheath. However, a single channel can provide a visible indicatorfor the blood flash. The two channels preferably extend along the lengthof the extruded tubular body. While the illustrated embodiment includesone or more channel disposed between the dilator and the sheath, one ormore channels can in addition or in the alternative be formed betweenthe needle and the dilator, within the dilator, and/or within thesheath. In some embodiments, the dilator 24 thus is made partially orcompletely from clear, translucent, transparent, or semi-opaque materialto visualize the fluid flash within the channel.

With reference back to the illustrated embodiment, the extruded tubularbody is cut to the appropriate length for a single dilator. In thepreferred method, the two OD grooves extend for the entire length of thecut dilator.

A tipping process is then employed on an end of the cut dilator toreform the tip. An end of the cut dilator is forced into a die/mandrelhaving geometry that matches the desired geometry of the tip of thefinished dilator. The desired geometry is selected depending on, forexample, the inside diameter of the sheath. It is desirable for thesheath and dilator to form a close fit or seal near the tip to promoteblood flow in the proximal direction up the channel formed between thegrooved dilator and sheath. Preferably, the OD of the dilator in the tipregion tapers in the distal direction.

When in the die/mandrel, thermal energy is applied to the tip to reformthe tip to match the die/mandrel. The thermal energy may be applied byany known technique, including using radiant heating from an infrared orRF heat source. As part of the tipping process, the dilator in the tipregion is reformed so that the grooves are essentially removed. With thegrooves removed, the dilator is able to form the close fit or seal withthe sheath near the tip. The grooves are maintained along the remainderof the dilator on the proximal side of the location where the tip of thesheath 26 sits on the dilator. After removal from the die/mandrel, thetip end of the dilator may be cleaned and cut as necessary to remove anymanufacturing remnants.

The one or more fenestrations in the dilator is cut through the dilatornear the tip region and in or near the groove. Each fenestration may becut by any known means, including a drill or laser. Further, the cuttingdevice may be moved with respect to the dilator or vice versa to achievean oblong or other shape for the fenestration.

The end of the dilator opposite from the tip end can be flared tofacilitate over molding the dilator hub onto the dilator.

FIG. 4A is a plan view of the sheath 26 of the embodiment depicted inFIG. 1A. FIG. 4B is a cross-sectional view of the sheath 26 of theembodiment depicted in FIG. 4A, taken along line 4B-4B. FIG. 4C is anenlarged proximal end view of the sheath 26 of FIG. 4A. FIG. 4D is anenlarged perspective view of the sheath hub 42 of the sheath 26 of FIG.4A. As shown in FIGS. 4A-4D, the sheath 26 may comprise a sheath body40, a sheath hub 42, a distal portion 90, and a proximal region 92. Thesheath body 40 may be made partially or completely from clear,translucent, transparent, or semi-opaque material. The sheath body 40can also include one or more radiopaque markers, such as, for example,barium sulfate stripes. In a preferred embodiment, the sheath includestwo such radiopaque stripes disposed on diametrically opposite sides ofthe body 40.

The sheath body 40 may be a single piece sheath through which a catheteror other medical article (e.g., a guidewire) is inserted into thevessel. In such an embodiment, the sheath body 40 forms a conduit forinsertion of the catheter or other medical article (e.g., a guidewire).In addition to providing a conduit, the sheath or a portion of thesheath can form a lumen that is in addition to the lumen(s) of thecatheter. For example, an equivalent to a triple lumen catheter can beformed by inserting a dual lumen catheter through the sheath body 40with the sheath body 40 itself forming a third lumen.

It may be advantageous to remove a portion or the entire sheath body 40depending on the type of catheter or medical article that is to beinserted into the vessel after employing the access device 20. Forexample, after the catheter or other medical article is inserted intothe vessel, a portion of the sheath body 40 can be separated orpeeled-away and removed. A peel-away sheath can include perforations,serrations, skives, or other structures, or include other materials(e.g., PTFE with bismuth) to allow the physician or healthcare providerto remove easily a portion or the entire sheath body 40.

The sheath hub 42 may include a luer slip connection and a lock member94. The locking member 94 may comprise a locking or attaching structurethat mates or engages with a corresponding structure. For example, thelock member 94 can be a luer connection 94 which can be configured toengage with the second luer connection 80 of the dilator hub 38.

The sheath hub 42, as best seen in FIGS. 4C and 4D, preferably isdesigned so that the locking mechanism or second luer connection 80 ofthe dilator hub 38 can enter the sheath hub 42 substantiallyunobstructed. However, in use, once the sheath hub 53 is placed at adesired location over the dilator shaft 36, the physician or healthcareprovider can push, pull, or twist the sheath hub 42 and possiblydisengage or engage the locking member 94 with a corresponding connectoron another medical article. The locking member 94 can be, for example, aluer connection, a protruding bump, dent, etc., that creates amechanical fit so that the dilator hub 38 and the sheath hub 42 arereleasably interlocked. In the illustrated embodiment, the lockingmember 94 of the sheath hub 42 comprises a luer connection. The sheathhub 42 preferably engages with the corresponding second luer connection80 on the dilator hub 38. Preferably, the locked position can bedisengaged or engaged by pulling, squeezing, pushing or twisting thedilator hub 38 relative to the sheath hub 42.

In some embodiments, the sheath hub 42 can comprise a lip 95. The lip 95can be threaded to allow the sheath hub 42 to attach to other medicalarticles with a corresponding locking feature.

The sheath hub 42 preferably comprises one or more surface features toallow the physician or healthcare provider to easily grasp or manipulatethe sheath 26 and/or access device 20. In the illustrated embodiment,the sheath hub 42 includes a squared grip 96 and ridges 98.

In additional embodiments, the sheath hub 42 may comprise radiallyextending wings or handle structures to allow for easy release andremoval of the sheath body 40 from other parts of the access device 20.In some applications, the wings are sized to provide the healthcareprovider with leverage for breaking apart the sheath hub 42. Forexample, the sheath hub 42 may comprise a thin membrane connecting thehalves of the sheath hub 42. The membrane is sized to keep the halves ofthe sheath hub 42 together until the healthcare provider decides toremove the sheath hub 42 from the access device. The healthcare providermanipulates the wings to break the membrane and separate the sheath hub42 into removable halves.

FIG. 5A is a perspective view of the guidewire section 28 of theembodiment depicted in FIG. 1A. FIG. 5B is a plan view of the guidewiresection 28 depicted in FIG. 5A, which preferably includes the guidewirehub 46. The guidewire hub 46 can comprise one or more surface featuresto allow the physician or healthcare provider to easily grasp ormanipulate the guidewire hub 46 and/or access device 20. In theillustrated embodiment, the guidewire hub 46 comprises one or moreridges 110. In a pre-loaded state, the outer surface of the guidewirehub 46 engages with a locking mechanism 130 on the track 30 when theguidewire hub 46 is in a third position 125.

In some embodiments, the guidewire 44 may form a close fit with theinside diameter of the needle body so as to provide a self-aspiratingfunction when retracted. For example, an outside diameter of theguidewire 44 may be selected to form a close fit with the needle alongthe length of the guide wire or along only a portion of the guidewire44.

In some embodiments, the distal end portion of the guidewire can have areduced diameter in comparison to other sections of the guidewire. Thesize of such reduced diameter section can be selected to permit fluid topass to the fenestration 56 in the needle body even when the guidewirehas been advanced beyond the distal tip of the needle.

FIG. 6A is a perspective view of the track 30 of the embodiment depictedin FIG. 1A. FIG. 6B is a plan view of the track 30 illustrated in FIG.6A. FIG. 6C is a side view of the track 30 illustrated in FIG. 6A. Asshown in FIGS. 6A-6C, the track 30 in the illustrated embodimentcomprises a distal portion 120, a proximal portion 122, a distal lockingmember 124 that connects the track to the dilator hub 38, a lockingmechanism 128 that inhibits further proximal and distal movement of theneedle hub 34 once the needle hub 34 is slid from the first position 121to the second position 123 along the track 30, and a locking mechanism130 that allows the guidewire hub 46 to attach to the track 30 when theguidewire hub is in the pre-loaded state or third position 125.Preferably, the track is made of polycarbonate material; however, asexplained below, other materials can be used.

The track 30 may further include a track section 132 of reduced width asshown most clearly in FIGS. 6A and 6B. The reduced width facilitatesassembly of the needle hub to the track 30. The illustrated embodimentincludes a rib 133 on the distal portion 120 of the track 30. The rib133 provides additional structural reinforcement between the distallocking member 124 and the remainder of the track 30.

As illustrated in FIG. 1A, the distal locking member 124 connects to thedilator 24 and allows the track 30 to extend proximally from the dilator24. For example, the locking member 124 can comprise two curved arms 124that connect to the dilator hub 38 between the dilator hub lip 77 andthe dilator hub base 79. The locking member 124 limits movement of thetrack 30 in a distal or proximal direction relative to the dilator hub38 but allows the track 30 to rotate freely around the dilator hub 38.

FIG. 6D is an enlarged view of a portion of the embodiment depicted inFIG. 6B. As shown, the locking mechanism 128 is formed by varying thewidth of the track in the region of the second position 123. Forexample, the illustrated embodiment includes a track section 134 ofincreasing width in the distal direction, a track section 136 of reducedwidth distal to the track section 134 of increasing width, and twofinger elements 138. The two finger elements 138 project from the distalend of the track section 136 toward the proximal end of the track 30 andflare away from the longitudinal axis of the track 30.

FIG. 6E is an enlarged view of a portion of the embodiment depicted inFIG. 6B. The locking mechanism 130 is formed by a clip, clasp or otherstructure that engages with a portion of the guidewire hub or with aportion of the track 30 when the guidewire hub is in the third position.Some or all of the engagement structure may be part of the track 30, bepart of the guidewire hub, or be split between the track 30 andguidewire hub. In the illustrated embodiment, the locking mechanism 130extends from the track 30 and engages with the guidewire hub. Thelocking mechanism 130 comprises a rectangular element 140 protrudingfrom the track 30, two track arms 142 projecting from the track 30distal to the rectangular element 140, and a stop 144 protruding fromthe track 30 distal to the track arms 142.

In the illustrated embodiment, the locking mechanism between the needlehub and the dilator resides on the proximal side of the dilator hub. Inother embodiments, however, the locking mechanism can be disposed atother locations as well. For example, where the locking mechanismincludes two pivotal levers which are joined by a locking hinge, thelocking mechanism can be disposed radially relative to the needle hub.In such an embodiment, one lever is pivotally coupled to the dilator andthe other lever is pivotally coupled to the needle. When the needle hubis moved away from the dilator hub, the levers straighten to a pointwhere the hinge locks. A similar effect can be obtained by a tetherlimiting proximal movement of the needle hub relative to the dilatorbeyond a particular point, thereby locking the components together. In afurther embodiment, an elongated structure can extend parallel to theneedle body from the needle hub within the dilator. Once the needle hubis moved a sufficient distance away from the dilator, additionalstructure of the locking mechanism (e.g., a detent) engages theelongated structure to inhibit further movement of the needle relativeto the dilator. Accordingly, as illustrated by these additionalembodiments, the locking mechanism operating between the needle and thedilator can be disposed at a variety of locations relative to thedilator hub.

FIG. 7A is an enlarged plan view of the access device of the embodimentdepicted in FIG. 1A pre-loaded with the guidewire. FIG. 7B is a sideview of the embodiment depicted in FIG. 7A. FIG. 7C is a cross-sectionalview of the embodiment depicted in FIG. 7A along line 7C-7C. FIG. 7D isa proximal end view of the access device 20 of FIG. 7A. In thispre-loaded state, the guidewire hub 46 is locked to the track 30 whenthe guidewire hub 46 is located in a third position 125. In thisposition, the guidewire hub 46 can be secured to the track 30 betweenthe rectangular element 140 and the stop 144. For example, the guidewirehub 46 can releasably lock between the rectangular element 140 and thestop 144. In addition, the track arms 142 can further secure theguidewire hub 46 to the track 30. This locking mechanism can arrestunintended rotational and axial movement of the guidewire 44 at least inthe distal direction when the guidewire hub 46 is in the third position125. Of course, the healthcare provider may disengage the guidewire hub46 from the track 30 to allow distal movement of the guidewire throughthe access device 20.

In the preloaded-state illustrated in FIGS. 7A-7C, the needle hub 34 islocked to the dilator hub 38 when the needle hub 34 is in the firstposition 121. Preferably, in the locked position, the openings orfenestrations in the needle and dilator are in register or in alignmentwith each other. When locked, the needle 22 and the dilator 24 areinhibited from at least unintentional rotational and axial movementrelative to each other. By preventing unintentional rotation of thedilator hub with respect to the needle 34, the fenestrations or openingsmaintain their general alignment.

In the pre-loaded state, the dilator hub 38 is secured to the sheath hub42. This can inhibit at least unintentional rotational and axialmovement between the dilator 24 and the sheath 26. In embodiments wherethe sheath hub 42 and the dilator 24 have only a luer slip connection,the dilator 24 and sheath hub 42 may rotate relative to each other.

FIG. 8A is a plan view of the embodiment depicted in FIG. 1A thatillustrates an operational step of one method of using the access device20. FIG. 8A depicts the needle body 32 of the access device 20 insertedinto a vessel 148, such as a vein. While the described method refers tovascular access, the access device 20 also can be used to access andplace a catheter or sheath into other locations within a patient's body(e.g., for draining an abscess) and for other purposes.

FIG. 8B is an enlarged plan view of the portion of the embodimentillustrated in FIG. 8A which is circled by line 8B-8B. FIG. 8C is anenlarged plan view of the portion of the embodiment illustrated in FIG.8B which is circled by line 8C-8C. FIG. 8D is an enlargedcross-sectional view of the embodiment depicted in FIG. 8C along line8D-8D.

As noted above, the needle body 32 comprises one or more side openings56 in its side wall. The dilator shaft 36 comprises one or more sideopenings 74. The side openings 56, 74 may have the same or differentshapes as well as aspect ratios. In the illustrated embodiment, the sideopening 56 in the needle body 32 has a different aspect ratio than theside opening 74 in the dilator shaft 36. The side opening 56 in theneedle body 32 is elongated in one direction (e.g., substantiallyparallel to the longitudinal axis of the needle body 32). The sideopening 74 in the dilator shaft 36 is elongated in a different direction(e.g., along the circumference of the dilator shaft 36). Having offsetelongated openings 56, 74 in the needle body 32 and the dilator shaft 36increases the likelihood that the openings 56, 74 in the needle body 32and dilator shaft 36 will be sufficiently aligned so that blood flowsthrough the needle side opening 56 and dilator side opening 74. FIGS.8A-D illustrate the alignment between only one set of corresponding sideopenings. Other sets of side openings can also be aligned or bemisaligned depending upon the relative orientations of the needle body32 and the dilator shaft 36.

In the illustrated embodiment, the dilator shaft 36 is coaxiallypositioned to minimize an annular space 150 between the needle body 32and the dilator shaft 36. The inner surface 152 of the dilator shaft 36need not, though it can, lie directly against the outer-surface 154 ofthe needle body 32. Preferably, in this embodiment, the annular space150 between the outer-surface 154 of the needle body 32 and the innersurface 152 of the dilator shaft 36 is minimized to inhibit the flow ofblood or its constituents (or other bodily fluids) into the annularspace 150 between the dilator shaft 36 and needle body 32.Advantageously, this feature minimizes the blood's exposure to multipleexternal surfaces and reduces the risk of contamination, infection, andclotting.

As illustrated in FIG. 8A, the dilator shaft 36 is coaxially mounted tothe needle body 32 such that at least part of one side opening 56disposed on the needle body 32 is rotationally aligned with at leastpart of one side opening 74 on the dilator shaft 36. Preferably, theneedle body 32 and dilator shaft 36 maintain rotational alignment sothat blood flows through the needle side opening 56 and dilator sideopening 74.

The sheath body 40, as noted previously, is preferably made partially orcompletely from clear, semi-opaque, translucent, or transparent materialso that when blood flows into the needle body 32, (1) through the needleside opening 56, (2) through the dilator side opening 74, and (3) into achannel 156, the physician or healthcare provider can see the blood. Insome modes, the channel 156 is formed between the dilator shaft 36 andthe sheath body 40 and defined by one or more ridges 76 on the dilatorshaft 36. In some modes, the channel 156 is formed within a wall of thedilator shaft 36 with the dilator shaft 36 preferably comprising atransparent material. Blood will indicate to the physician or healthcareprovider that the bevel tip 54 of the needle body 32 has punctured avessel 148.

In some embodiments, the needle body 32 and dilator shaft 36 may (both)have multiple side openings where some or all of these side openings canbe rotationally aligned.

The channel 156 can have an axial length that is almost coextensive withthe length of the sheath 26. In other embodiments, the channel 156 canbe significantly smaller than the elongated channel 156 just described.For example, but without limitation, the channel 156 can be disposedwithin a distal, mid and/or proximal portion(s) of the sheath 26. Thechannel 156 alternatively can have a linear, curved or spiral shapealong an axial length of the sheath 26 or can be formed by a pluralityof such shapes. The channel 156 may have various thicknesses and spanangles. The thickness of the channel 156 can range from almost close tozero to 0.010 inches. Preferably, the channel 156 has a thickness ofabout 0.0005 to about 0.003 inches. More preferably, the channel 156 canhave a thickness of about 0.001 inches to about 0.002 inches. Thechannel 156 can have a span angle Φ about the axis of the dilator 24 ofabout 30 degrees to about 210 degrees or more, but preferably less than360 degrees. More preferably, the channel 156 can have a span angle Φ ofabout 60 to 150. In the illustrated embodiment, the channel 156 spans120 degrees. The thickness and span angle Φ can be chosen so as tooptimize the capillary action that occurs within the channel 156 asfluid (e.g., whole blood) enters the channel 156 as may further beselected based on the expected pressure in the body cavity and viscosityof the liquid.

FIGS. 8E-8G are graphs of test data illustrating how quickly a fluid isdrawn up the surfaces of the channel 156 when the span angle is 120degrees, the contact angle (θ) is 5 degrees, and the circumferentiallength (H) is 0.64 mm at 60 degrees. On each graph, the filling length(mm) is plotted on the y-axis, and time (seconds) is plotted on thex-axis. The tests were performed at hydrodynamic pressures similar topressures experienced in peripheral vessels. FIG. 8E illustrates therate fluid is drawn up a channel 156 with a gap height width of 0.002inches, FIG. 8F illustrates the rate fluid is drawn up a channel 156with a gap height width of 0.001 inches, and FIG. 8G illustrates therate fluid is drawn up a channel 156 with a gap height width of 0.0005inches. As shown in FIGS. 8E-G, fluid is drawn up the fastest in achannel with a gap height width of 0.0005 inches, followed by a channelwith a gap height width of 0.001 inches, followed by a channel with agap height width of 0.002 inches.

The shape of the channel 156 described above and the resulting capillaryaction was optimized for use with whole blood as opposed to other fluidshaving a different viscosity than whole blood (e.g. leukocytes, pus,urine, plasma). However, the shape of the channel 156 is not limited tothe disclosed shape and may be optimized for draining other liquids,such as pus. Further, the shape of the channel 156 described above wasoptimized for peripherally located vessels where the pressure in thevessel enhances the capillary action and resulting blood flash as wellas for vessels located in the regions where the pressure may be low. Forexample, in the thorax region of the body, the expected pressure in theveins may be lower than in a peripherally located vein when the patientbreathes. A different size of the channel for use of the access device20 in other regions of the body may be employed taking into account theexpected pressure within the vessel or body cavity.

Additionally, an outer-surface 160 of the dilator shaft 36 and/or aninner surface 158 of the sheath body 40 can be coated with a substanceto promote or enhance the capillary action within the channel 156. Forexample a hydrophilic substance can be used to coat outer-surface 160 ofthe dilator shaft 36 and/or the inner surface 158 of the sheath body 40to enhance capillary action. Similarly, one or both of these componentscan be made of a hydrophilic material. A hydrophilic substanceadditionally can be applied to the outer surface of the sheath 26 to actas a lubricant to ease insertion of the sheath 26 into a patient. Otherlubricants or lubricous coatings can be used on the exterior of thesheath 26 or at least the outer surface of the sheath can be formed of alubricous material. Additionally, the sheath 26 can be coated or formedwith agents (e.g., heparin), which elute from the sheath, to facilitatethe clinical application of the access device 20.

FIG. 8H is a cross sectional view of the embodiment depicted in FIG. 8Calong line 8H-8H. In this region of the illustrated access device 20,the sheath body 40 is coaxially positioned to minimize the annular space157 between the sheath body 40 and the dilator shaft 36 while stillallowing relative movement of the sheath body 40 and the dilator shaft36. The inner surface 158 of the sheath body 40 need not, though it can,lie directly against the outer-surface 160 of the dilator shaft 36. Theannular interface 157 between the outer-surface 160 of the dilator shaft36 and the inner surface 158 of the sheath body 40 may be reduced inthis region to inhibit the distal flow of blood or its constituents (orother bodily fluids) from the opening 74 in the dilator shaft 36.

FIG. 8I is an enlarged plan view of the portion of the embodimentillustrated in FIG. 8A which is circled by line 8I-8I. FIG. 8J is across-sectional view of the embodiment depicted in FIG. 8I. FIGS. 8I and8J illustrate the needle hub 34 locked to the dilator hub 38 when theneedle hub is in the first position 121. The dilator shaft 36 may becoaxially mounted to the needle body 32 by slipping a hollow section 84of the dilator shaft 36 over the needle body 32 and releasably securingthe dilator hub 38 to the needle hub 34. The proximal end 86 of thedilator hub 38 is configured to mechanically fit and interlock with theneedle hub 34.

The dilator shaft 36 may be releasably mounted to the needle body 32 sothat the dilator shaft 36 can be mounted and released, or vice versa,from a coaxial position relative to the needle body 32. This lockingmechanism can inhibit at least some unintentional rotational and axialmovement between the needle 22 and the dilator 24 when the needle hub 34is in the first position. As shown, the needle hub 34 may have a luerconnection 64 that locks to the luer connection 78 of the dilator hub38. Furthermore, the needle hub 34 may also have latch element 66 thatlocks to the opening 82 in the dilator hub 38.

In addition, FIGS. 8I and 8J illustrate the dilator hub 38 engaged withthe sheath hub 42 when the access device 20 is inserted into a vessel148. Preferably, the proximal end 86 of the sheath hub 42 is configuredto mechanically fit and releasably engaged with the dilator hub 38. Asshown, the luer connection 80 in the dilator hub 38 can engage with thelock member 94 of the sheath hub. The resulting friction fit can inhibitat least some unintentional rotational and axial movement between thedilator 24 and the sheath 26 when the access device 20 is inserted intoa vessel 148.

FIG. 9A is a side view of the embodiment depicted in FIG. 1A thatillustrates a further operational step of the access device 20. FIG. 9Adepicts the guidewire 44 of the access device 20 advanced in a distaldirection into a vessel 148. This can be achieved by advancing guidewirehub 46 from the third position 125 in a distal direction. The guidewirehub 46 is then locked to the needle hub 34 when the needle hub 34 is inthe first position 121.

FIG. 9B is an enlarged side view of the portion of the embodimentillustrated in FIG. 9A which is circled by line 9B-9B. FIG. 9C is across-sectional view of the embodiment depicted in FIG. 9B. FIG. 9Cillustrates the locking mechanism between the guidewire hub 46 and theneedle hub 34. Preferably, the guidewire hub 46 is configured tomechanically fit and releasably or irreversibly interlock with theneedle hub 34. As shown, the guidewire hub 46 includes a nub 162 on theinner surface of the guidewire hub 46. The nub 162 of the guidewire hubcan lock onto the needle hub 34 by advancing the guidewire hub 46 in adistal direction until the nub 162 is secured within the threaded grooveon the lip of the needle hub 46. In other embodiments, the guidewire hub46 can lock to the needle hub 34 via corresponding threaded elements.

FIG. 10A is a side view of the embodiment depicted in FIG. 1A thatillustrates another operational step of the access device 20. FIG. 10Adepicts the dilator shaft 36 and the sheath body 40 advanced in a distaldirection into a vessel 148. This can be achieved by releasing thedilator hub 38 from the needle hub 34 and advancing the dilator 24 andsheath 26 in a distal direction relative to the needle hub 34 along theguidewire and needle. FIG. 10A further illustrates the proximal movementof the needle 22 and guidewire section 28 relative to the dilator 24 andthe sheath 26. The needle hub 34 will lock to the track 30 when theneedle hub 36 reaches the second position 123.

FIG. 10B is an enlarged rear view of the portion of the embodimentillustrated in FIG. 10A which is circled by line 10B-10B. As depicted inFIG. 10B, the needle hub 34 locks onto the track 30 via the lockingmechanism 128 in the second position 123. The needle hub tangs 68 slidein a proximal direction over the track fingers 138 and the tangs 68 canlock into place between the track fingers 138 and the track section ofincreasing width 134. This arrests and, more preferably, substantiallyirreversibly prevent axial movement of the needle body 32 at least inthe distal direction when the needle hub 34 is in the second position123. In the illustrated embodiment, the locking mechanism 128irreversibly prevents the needle hub 34 from moving in either theproximal or distal directions once engaged. Furthermore, the distal tip54 of the needle 22 is drawn into the dilator 24 to sheath the distaltip 54 when the needle hub 34 is in the second position 123. Thus, thislocking mechanism 128 inhibits the bevel tip 54 disposed on the distalportion 50 of the needle body 32 from being advanced beyond the distalend of the dilator shaft 36 once the dilator shaft 36 has been advancedover the needle body 32 during use. The dilator shaft 36 thus sheathsthe sharp bevel tip 54 of the needle body 32 to inhibit accidentalneedle sticks from occurring.

FIG. 11A is a side view of the embodiment depicted in FIG. 1A thatillustrates the final operational step of the access device 20. FIG. 11Aillustrates the removal of the guidewire 44 and the dilator shaft 36from the vessel leaving the sheath body 40 properly inserted within thevessel 148. FIG. 11B is an enlarged plan view of the portion of theembodiment illustrated in FIG. 11A which is circled by line 11B-11B. Asclearly shown in FIG. 11B, the distal end of the dilator shaft 36 andthe guidewire 44 extend beyond the sharp bevel tip 54 of the needle body32 to inhibit accidental needle sticks from occurring.

As noted above, having openings 56, 74 in the needle body 32 and dilatorshaft 36 with different aspect ratios will increase the likelihood thatthe openings 56, 74 in the needle body 32 and dilator shaft 36 will bealigned so that blood flows substantially unobstructed through theneedle side opening 56 and dilator side opening 74.

In the following embodiments, structure from one embodiment that issimilar to structure from another embodiment share the same rootreference number with each embodiment including a unique suffix letter(32, 32A, 32B, etc.). FIG. 12A is a plan view of another embodiment ofthe openings 56, 74 in the needle body 32 and dilator shaft 36illustrated in FIGS. 8B and 8C. FIG. 12B is an enlarged cross-sectionalview of the embodiment depicted in FIG. 12A along line 12B-12B. FIGS.12A and 12B depict a needle body 32A with an oblong opening 56A and adilator shaft 36A with a circular opening 74A. In other embodiments, theneedle can have a circular opening and the dilator can have an oblongopening. These embodiments can increase the likelihood that the openings56A, 74A will be at least substantially aligned so that blood flowsthrough the needle side opening 56A and dilator side opening 74A.

FIG. 13A is a plan view of another embodiment of the openings 56, 74 inthe needle body 32 and dilator shaft 36 illustrated in FIGS. 8B and 8C.FIG. 13B is an enlarged cross-sectional view of the embodiment depictedin FIG. 13A along line 13B-13B. FIGS. 13A and 13B depict a needle body32B with a circular opening 56B and a dilator shaft 36B with a circularopening 74B that is larger than the circular opening 56B in the needlebody 32B. In other embodiments, the opening in the dilator can besmaller than the opening in the needle. These embodiments can alsoincrease the likelihood that the openings 56B, 74B will be at leastsubstantially aligned so that blood flows through the needle sideopening 56B and dilator side opening 74B.

As noted above, the dilator shaft 36 may have one or more channels 156formed between ridges 76 to form a conduit or flow path between thesheath body 40 and the dilator shaft 36 to enable the physician orhealth care provider to view the blood after the bevel tip 54 of theneedle body 32 has properly punctured a vessel or the channels may beformed without ridges but by extruding axial indentations of variouspossible configurations or by forming fully enclosed channels within thedilator shaft or body.

FIG. 14A is a plan view of another embodiment of the ridges 76 depictedin FIG. 8C. FIG. 14B is an enlarged cross-sectional view of anotherembodiment of the ridges 76 depicted in FIG. 8D. FIGS. 14A and 14Bdepict two ridges 76C on the inner surface 158C of the sheath body 40Cthat form at least one channel 156C between the sheath body 40C and thedilator shaft 36C.

FIG. 15A is a plan view of another embodiment of the ridges 76 depictedin FIG. 8C. FIG. 15B is an enlarged cross-sectional view of anotherembodiment of the ridges 76 depicted in FIG. 8D. FIGS. 15A and 15Bdepict two ridges 76D on the inner surface 158D of the sheath body 40Dand two ridges 76E on the outer surface 160D of the dilator shaft 36Dthat combine to form a channel 156D between the sheath body 40D and thedilator shaft 36D. For example, if the desired channel thickness isabout 0.001 inches, the two ridges 76D on the inner surface 158D of thesheath body 40D can each be about 0.0005 inches thick and the two ridges76E on the outer surface 160D of the dilator shaft 36D can each be about0.0005 inches thick.

FIG. 16A is a plan view of another embodiment of the ridges 76 depictedin FIG. 8C. FIG. 16B is an enlarged cross-sectional view of anotherembodiment of the ridges 76 depicted in FIG. 8D. FIGS. 16A and 16Bdepict many ridges on the outer surface 160E of the dilator shaft 36E.Between adjacent ridges are splines 76F. The splines 76F form aplurality of channels 156E between the sheath body 40E and the dilatorshaft 36E. One or more of the channels 156E can have the same span angleΦ or different span angles Φ. In the illustrated embodiment the channels156E have span angles of 120 degrees and 23 degrees. In anotherembodiment, a single ridge 76 can spiral around the exterior of thedilator along its length.

FIG. 17 is an enlarged cross-sectional view through another embodimentof the access device and shows the channel 156F formed between a medicalarticle or sheath body 40F and a dilator shaft 36F that have dissimilarshapes. In the illustrated embodiment, the outer surface of the dilatorshaft 36F has an oval shape while the inner surface of the sheath body40F has a round shape. The oval dilator shaft 36F and the adjacent roundsheath body 40F form one or more channels or gaps 156F between thesheath body 40F and the dilator shaft 36F. Of course the shapes of thesheath body 40F and dilator shaft 36F are not limited to round and ovaland may include any other combination of dissimilar shapes in adjacentregions of the sheath body 40F and dilator shaft 36F. In some modes, theouter surface of the dilator shaft 36F is oblong and the inner surfaceof the sheath body or medical article 40F is round. In some modes, theouter surface of the dilator shaft 36F is round and the inner surface ofthe medical article 40F is square. The gap or channel 156F can follow alongitudinal axis, a spiral path along the longitudinal axis, a linearpath along the longitudinal axis or other path along the access device.In some modes, the linear path is parallel to the longitudinal axis. Thegap or channel 156F thickness can vary along at least a portion of alength of the gap or channel 156F.

In other embodiments, the channel 156 can be formed by having onecomplete ridge on the inner surface of the sheath and one complete ridgeon the outer surface of the dilator. In other embodiments, the innersurface of the sheath can have two ridges that run 50% of the length ofthe channel 156 and the outer surface of the dilator can have two ridgesthat run the remaining 50% of the channel 156.

The embodiments herein described are comprised of conventional,biocompatible materials. For example, the needle preferably consists ofceramic, a rigid polymer, or a metal such as stainless steel, nitinol,or the like. The other elements can be formed of suitable polymericmaterials, such as polycarbonate, nylon, polyethylene, high-densitypolyethylene, polypropylene, fluoropolymers and copolymers such asperfluoro (ethylene-propylene) copolymer, polyurethane polymers orco-polymers.

As noted above, the present access device can be used to place acatheter at other locations within a patient's body. Thus, for example,but without limitation, the access device can be used as or with avariety of catheters to drain fluids from abscesses, to drain air from apneumotorax, and to access the peritoneal cavity. In such applications,body fluids flow into the viewing space to indicate when the needle hasbeen properly placed.

Although this invention has been disclosed in the context of certainpreferred embodiments and examples, it will be understood by thoseskilled in the art that the present invention extends beyond thespecifically disclosed embodiments to other alternative embodimentsand/or uses of the invention and obvious modifications and equivalentsthereof. In addition, while a number of variations of the invention havebeen shown and described in detail, other modifications, which arewithin the scope of this invention, will be readily apparent to those ofskill in the art based upon this disclosure. It is also contemplatedthat various combinations or sub-combinations of the specific featuresand aspects of the embodiments may be made and still fall within thescope of the invention. Accordingly, it should be understood thatvarious features and aspects of the disclosed embodiments can becombined with or substituted for one another in order to form varyingmodes of the disclosed invention. Thus, it is intended that the scope ofthe present invention herein disclosed should not be limited by theparticular disclosed embodiments described above, but should bedetermined only by a fair reading of the disclosure and the claims thatfollow.

1. An access device for placing a medical article within a body space,comprising: a needle having an elongated needle body with a distal endand a hub from which the needle body extends; a dilator disposed on theneedle body, the needle and the dilator being moveable relative to eachother from a first position, wherein the distal end of the needle liesdistal of the dilator, and a second position wherein the distal end ofthe needle lies within the dilator, the dilator including a dilator huband an elongated dilator shaft that extends from the dilator hub; and alocking mechanism operating between the needle and the dilator toinhibit movement of the needle relative to the dilator when in thesecond position, the locking mechanism being configured to allowmovement of the needle from the first position toward the secondposition without engagement by the locking mechanism so as to lessenresistance to the movement.
 2. The access device of claim 1, wherein alongitudinal length of the needle is greater than a longitudinal lengthof the dilator, and a distance between the first position and the secondposition is less than a longitudinal length of the needle.
 3. The accessdevice of claim 1 additionally comprising a medical article disposed onthe dilator, the medical article and the dilator being movable relativeto each other.
 4. The access device of claim 1, wherein the medicalarticle is a catheter.
 5. The access device of claim 1, wherein themedical article is a sheath.
 6. The access device of claim 5, whereinthe sheath is configured to receive at least a portion of a catheter. 7.The access device of claim 1, wherein the locking mechanism comprises afirst member supported on the proximal side of and spaced from thedilator hub and a second member supported by the needle, the first andsecond members being configured to engage each other when the needle hubis moved through a distance away from the dilator hub, said distancebeing greater than a distance by which the distal end of the needle bodyextends beyond the dilator when the hubs of the needle and dilator arejuxtaposed.
 8. The access device of claim 7, wherein an elongatedsupport suspends the first member of the locking mechanism at a locationspaced from the dilator hub.
 9. The access device of claim 8, whereinthe elongated support and the needle hub include cooperating structuresuch that the needle slides along the elongated support.
 10. The accessdevice of claim 9, wherein the elongated support is rotatably coupled tothe dilator hub.
 11. The access device of claim 8, wherein the elongatedsupport lies generally parallel to a longitudinal axis of the needlebody.
 12. The access device of claim 8, wherein the elongated supportextends to the proximal side of the dilator hub.
 13. The access deviceof claim 8 additionally comprising a guidewire extending distally from aguidewire cap, the guidewire cap being releasably coupled to theelongated support.
 14. The access device of claim 13, wherein theguidewire cap engages the elongated support at a location proximate ofthe first member of the locking mechanism.
 15. The access device ofclaim 1, wherein the needle body includes at least one fenestration andthe dilator shaft includes at least one fenestration that communicateswith the needle fenestration.
 16. The access device of claim 15, whereinone of said fenestrations has a greater dimension in at least onedirection than the other one of said fenestrations.
 17. The accessdevice of claim 15 additionally comprising a medical article coaxiallydisposed about the dilator shaft, and at least one elongated channelformed between the dilator shaft and the medical article that extendsalong at least a substantial portion of the length of the dilator shaft,the channel communicating with the fenestration in the dilator shaft andhaving a dimension, in a direction perpendicular to the length of thedilator shaft, that is less than a maximum outer diameter of the dilatorshaft.
 18. The access device of claim 15 additionally comprising amedical article coaxially disposed about the dilator shaft, and at leastone elongated channel formed between the dilator shaft and the medicalarticle that extends along at least a substantial portion of the lengthof the dilator shaft, the channel communicating with the fenestration inthe dilator shaft and having a span angle of less than 360 degrees abouta longitudinal axis of the dilator.